raise RuntimeError(‘DataLoader worker (pid(s) {}) exited unexpectedly‘.format(pids_str))RuntimeErro

In use today pytorch The following error occurred while loading data ：

raise RuntimeError('DataLoader worker (pid(s) {}) exited unexpectedly'.format(pids_str))
RuntimeError: DataLoader worker (pid(s) 4252, 17184) exited unexpectedly

A careful analysis of , The reason lies in num_workers

dataloader = DataLoader(dataset,batch_size=2,num_workers=2,shuffle=True)

It's a common mistake , Because it is not written in

if __name__ == "__main__":

resolvent ：

1. No multithreading , take num_workers Set to 0

2. Written in if __name__ =="__main__": below , Because calling sub threads , There must be a main thread .